Rb2S
Rubidium sulfide is a thermodynamically stable semiconducting compound composed of rubidium and sulfur.
About Rb2S
Rubidium sulfide is a semiconducting binary compound that sits firmly on the convex hull, indicating high thermodynamic stability. Its structural chemistry is well-documented, with a wide variety of reported phases that highlight its significance in fundamental materials research.
As a member of the alkali metal sulfide family, this material serves as a key subject for understanding ionic bonding and electronic behavior in chalcogenides. Its stability makes it a reliable candidate for investigating the properties of sulfur-based semiconductors in controlled environments.
Key Properties
Cross-validated computational properties for Rb2S, aggregated across 5 databases.
Band GapEnergy needed to move an electron from the valence band to the conduction band. Lower or zero values tend to behave more metallic; larger gaps are more insulating or semiconducting.
Energy Above HullThermodynamic distance from the most stable set of competing phases. 0 eV/atom is on the convex hull; small positive values may still be experimentally accessible.
StabilityA plain-language summary of the best reported energy-above-hull result. It reflects whether the lowest-energy structure is on, near, or far from the stability hull.
StructuresCount of reported calculated crystal structures for this formula, including alternate polymorphs, source databases, and observed space groups.
Cross-Source DFT Agreement
How well independent DFT databases agree on the thermodynamics of Rb2S. Tight agreement means computed properties can be trusted without re-running calculations.
Agreement ScoreA normalized confidence score summarizing how closely independent DFT databases agree. Higher scores mean tighter cross-source agreement.
Hull SpreadDifference between the highest and lowest energy-above-hull values reported by comparable sources. Smaller spread means less thermodynamic disagreement.
Sources ComparedNumber and names of computational sources with comparable entries for this formula.
Space Group ConsensusWhether independent sources predict the same crystal symmetry for the lowest-energy structure.
Reported Structures
Lowest-energy structures reported for Rb2S, ranked by energy above hull.
| Space GroupSymmetry classification of the crystal arrangement. The number is the international space-group index. | Crystal SystemBroad lattice family, such as cubic, tetragonal, monoclinic, or triclinic, derived from unit-cell symmetry. | Band Gap (eV)Electronic gap calculated for this specific reported structure, measured in electronvolts. | E above hull (eV/atom)Thermodynamic distance from the convex hull for this structure, normalized per atom. Lower is generally more stable. | E/atom (eV)Computed total energy normalized per atom. Use energy above hull, not this value alone, when comparing stability. | Density (g/cm³)Mass per relaxed crystal volume, reported in grams per cubic centimeter. |
|---|---|---|---|---|---|
| — | — | 2.21 | 0.0000 | -1.104 | — |
| Pnma (No. 62) | orthorhombic | 2.05 | 0.0000 | -1.189 | — |
| Pnma (No. 62) | orthorhombic | 2.05 | 0.0000 | -1.189 | — |
| Fm-3m (No. 225) | cubic | 1.96 | 0.0000 | -3.194 | 2.87 |
| — | — | 2.17 | 0.0002 | -1.103 | — |
| Pnma (No. 62) | orthorhombic | 1.97 | 0.0138 | -3.180 | 3.18 |
| Fm-3m (No. 225) | cubic | 1.98 | 0.0206 | -1.169 | — |
| — | — | 2.08 | 0.0274 | -1.076 | — |
| — | — | 2.17 | 0.0274 | -1.076 | — |
| — | — | 0.00 | 0.0275 | -1.076 | — |
| — | — | 1.92 | 0.0343 | -1.069 | — |
| P63/mmc (No. 194) | hexagonal | 2.27 | 0.0517 | -1.137 | — |
Applications
Where Rb2S is used.
Frequently Asked Questions
Common questions about Rb2S, answered from cross-validated data.
What is Rb2S?
Rubidium sulfide is a thermodynamically stable semiconducting compound composed of rubidium and sulfur.
What is Rb2S used for?
What is the band gap of Rb2S?
Is Rb2S a metal, semiconductor, or insulator?
Is Rb2S thermodynamically stable?
What is the crystal structure of Rb2S?
How many polymorphs of Rb2S are known?
What elements does Rb2S contain?
Where does the data for Rb2S come from?
How It Compares
As a stable binary sulfide, Rb2S serves as a benchmark for understanding the electronic and structural trends within the alkali metal chalcogenide class, providing a foundation for comparing the behavior of lighter or heavier group one sulfides.
Data sources & attribution
- oqmd — Data from the OQMD (oqmd.org). Cite: Saal et al., JOM 65, 1501 (2013); Kirklin et al., npj Comp. Mater. 1, 15010 (2015). (CC-BY-4.0)
- jarvis — Data from JARVIS (jarvis.nist.gov), NIST. Cite: Choudhary et al., npj Comp. Mater. 6, 173 (2020). (LicenseRef-US-Gov-PD)
- materials_project — Data from the Materials Project (materialsproject.org). Cite: Jain et al., APL Materials 1, 011002 (2013). (CC-BY-4.0)
- mpaloe — Data from MP-ALOE. Cite: Kuner et al., npj Comput. Mater. (2025), doi:10.1038/s41524-025-01834-9.
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